In vivo proteins and other extracellular matrix (ECM) components form an interlinking mesh in which cells integrate and interact. One way to mimic this natural architecture is through crosslinking artificial polymers to create 3 dimensional cell culture systems.
The cell culture and tissue engineering fields are well developed and a variety of ECM equivalents have been developed. These equivalents vary in the material that is used for a scaffold and consequently in the type cells that are capable of propagating therein.
Fibronectin (FN) is a predominant ECM protein that mediates cell attachment and growth. FN contains several ligands, including the tripeptide RGD and the peptide PHSRN (SEQ ID NO:40), which mediate cell adhesion. Naturally derived proteins such as fibronectin can be useful as scaffolds for in vitro cell attachment. However, a potential problem with any animal derived protein is the possibility of disease transmission.
Accordingly a range of engineered 3 dimensional scaffolds, which recreate the native 3 dimensional tissue, have been suggested. Current 3 dimensional scaffolds are not ideal (7). For instance, it is difficult to produce a scaffold which is specific for a particular cell line or tissue type; there is also among these scaffolds a high batch-to-batch variability; it is complicated to change a single property of these scaffolds without interfering with others. For example, if one would like to alter the viscosity of a particular scaffold one can eventually modify simultaneously the adhesion ligand density and mode of presentation or the porosity of the scaffold which could influence the diffusion properties of nutrients through the scaffold (11).
Accordingly, there remains the need for the provision of an improved cell culture environment.